Corvette Cylinder Heads - On The Warpath, Part 1

Putting World Products' New LS1X "Warhawk" Heads To The Test

In an effort to capitalize on the phenomenal performance potential of GM's LS engine family, the aftermarket has released a bevy of cylinder-head castings to cover everything from 3.90-inch (LS1) bore sizes through 455ci strokers featuring up to 4.125-inch bores. You can now add one more player to that list, as Bill Mitchell Racing Products (aka World Products) has finally released its long-awaited Warhawk LS1X aluminum heads.

According to Charlie Amodeo of World Products, "The LS1X head is a clean-sheet design that features factory 15-degree valve angles and is primarily targeted at [customers] looking for excellent power potential at reasonable prices. The heads flow over 300 cfm on the intake and are built with lots of extra material to allow additional porting and airflow gains."

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World Products' Warhawk LS1X aluminum heads are available with either 64 or 72cc combustion chambers. Bare heads retail at $1,157.98 for a pair (PN 025150 for 64cc or 025250 for 72cc). The heads have thick (0.650-inch) decks, and the valve-cover rails have been raised 0.300-inch to support aftermarket rocker arms. World also offers fully prepared heads that utilize Manley valves and springs to support either 0.600- or 0.700-inch valve lifts. These retail for $1,724.98 for the 0.600-lift package and $1,869.98 for the 0.700-lift version.

"The heads [in this story] were actually pre-production units sent to us for evaluation and product testing," says Pete Incaudo of VMax Motorsports. "Through a long-standing affiliation with Bill Mitchell and World, we worked toward the goal of getting them very close to what would ultimately be offered by World in the retail market. Since I have performed numerous cylinder-head evaluation tests for GM-including pre-production LS1 castings in 1996-it was a great opportunity to evaluate the World design and provide feedback. In addition to testing the heads on a flowbench, we wanted to see how much power could be generated on the dyno."

Follow along as we install a set of the new LS1X heads on an '02 Z06 owned by Kevin Turner of Carrollton, Texas. Other than a Halltech C5 Venom air-induction system, the car was bone stock prior to our ministrations. To help us extract maximum power from the combo, VMax and Real Performance Motorsports (RPM) spec'd out a nasty combination featuring Kooks headers, a rowdy Comp bumpstick, and a FAST intake manifold with a ported 90mm LS2 throttle body. Installation was performed at RPM HQ in Lewisville, Texas, by technicians Manuel Bejar and shop manager Keith Lohse. Company co-owner Brian Lohse, meanwhile, tuned the combination with HP Tuners' VCM Suite software.

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After putting a fresh fill of Dexcool in the radiator and recharging the A/C, RPM tops off the FAST manifold with a VMax ported 90mm LS2 throttle body and integrates the system with a Casper's Electronics throttle-body-adapter harness. After connecting the battery and reinstalling the Halltech air assembly, a final visual check is performed before the engine is brought to life. Once it is verified that there are no leaks, RPM loads the Z06 onto the chassis dyno, and Brian Lohse begins the process of creating a custom tuning program to maximize the combination. Check back next month for the results.